JP3470328B2 - Polyisocyanate composition excellent in low-temperature storage stability and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyisocyanate composition containing a carbodiimide group and a uretonimine group or containing a uretonimine group and a method for producing the same. More specifically, it relates to a carbodiimide group- and uretonimine group-containing or uretonimine group-containing polyisocyanate composition having significantly improved low-temperature storage stability, and a method for producing the same.

[0002]

2. Description of the Related Art So-called carbodiimide-modified MDI (abbreviated as liquid MDI) obtained by adding an alkyl phosphate catalyst or phosphorene catalyst to diphenylmethane diisocyanate (abbreviated as MDI hereinafter) and reacting at an appropriate temperature is a coating material. It is used as a raw material for thermosetting elastomers and foams. Conventionally, liquid MDI is 2,
Manufactured from so-called MDI having a low isomer content, wherein the total of 2'-MDI and 2,4'-MDI is 0.1 to 8% by weight and 4,4'-MDI is about 99.9 to 92% by weight. There is. For this reason, when exposed to a low temperature such as being left outdoors in winter, crystals of 4,4'-MDI, which is the main component, are deposited in a few days, which makes it difficult to use. As a measure against this,
Insulation and heat dissolution during storage are performed, but there have been problems such as an increase in heat insulation and heating costs and an increase in the number of steps.

[0003]

Even when used in winter or in cold regions, it exhibits sufficient storage stability for a long period of time without consideration of the preservation method, and when used for the above-mentioned purposes, it has a conventional liquid form. A new liquid M that has the same performance as MDI
The purpose was to provide DI.

[0004]

Means for Solving the Problems The inventors of the present invention have completed the present invention as a result of extensive studies to solve the above problems.

That is, the present invention is the following (1) to (4) . (1) Isocyanate group is carbodiimidated
The constituent components of the polyisocyanate composition including
The total of 2,2'-MDI and 2,4'-MDI is 10-5
0% by weight and 90 to 50% by weight of 4,4'-MDI
A porpoie obtained by carbodiimidating a part of MDI
In the lisocyanate composition, 2,2'-MDI and
The total of 2,4'-MDI is 0.1 to 10% by weight, and
MD consisting of 4,9'-90% by weight of 4,4'-MDI
A carbodiimidization catalyst was added to the composition (b) and heated.
Part of the MDI composition (b) is carbodiimidized to
The total of 2,2'-MDI and 2,4'-MDI is 15
~ 60% by weight, and 85-40% by weight of 4,4'-MDI
And characterized by mixing MDI composition (c) consisting of%
Polyisocyanate composition with excellent low temperature storage stability
Method of manufacturing things.

(2) In a polyisocyanate composition obtained by carbodiimidating a part of MDI and uretoniminating the generated carbodiimide group, a polyisocyanate composition in which the isocyanate group is carbodiimidated and uretoniminated or uretoniminated is included. The polyisocyanate composition comprises 10 to 50% by weight of 2,2'-MDI and 2,4'-MDI, and 4,
A polyisocyanate composition having excellent low-temperature storage stability, characterized in that 4'-MDI is 90 to 50% by weight.

(3) 2,2'-MDI and 2,4'-M
The total amount of DI is 10 to 50% by weight, and 4,4'-MDI
Is added to the MDI composition (a) containing 90 to 50% by weight, and the carbodiimidization catalyst is added to the MDI composition (a) to heat the MDI composition (a).
A part of carbodiimide is formed, and then the carbodiimide group formed is uretoniminated.
(2) A method for producing a polyisocyanate composition having excellent low temperature storage stability as described in (1) .

(4) 2,2′-MDI and 2,4′-M
Total DI is 0.1 to 10% by weight, and 4,4'-MD
MDI composition (b) in which I is 99.9 to 90% by weight
A carbodiimidization catalyst is added to the mixture and heated to carbodiimidate a part of the MDI composition (b), and then the carbodiimide group thus formed is uretoneimine.
The above MDI composition (c) is mixed, wherein the total of 2'-MDI and 2,4'-MDI is 15 to 60% by weight, and 4,4'-MDI is 85 to 40% by weight.
(2) A method for producing a polyisocyanate composition having excellent low temperature storage stability as described in (1) .

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
The outline of the industrial manufacturing method of MDI is shown in the following three steps. (1) A polyamine containing diaminodiphenylmethane as a main component is obtained by a condensation reaction between aniline and formaldehyde. (2) By reacting this polyamine with phosgene, crude MDI containing MDI as a main component is obtained. (3) Obtain MDI from the crude MDI by fractional distillation.

Therefore, the isomer distribution of MDI is determined by the first stage condensation reaction. In this condensation reaction,
Dinuclear, trinuclear, and polynuclear bodies are produced. The binuclear body has two benzene rings in one molecule obtained by reacting 2 mols of aniline and 1 mol of formaldehyde, and the trinuclear body is 3 mols of aniline and 2 mols of formaldehyde. Has 3 benzene rings in one molecule, and a polynuclear body has 4 benzene rings in one molecule.
Have more than one.

In the binuclear body, the 4,4'-isomer bound at the para-para position is most produced, and then the 2,4'-isomer bound at the para-ortho position is the least produced. Becomes the 2,2'-isomer linked at the ortho-ortho position. These ratios can be easily controlled by changing the condensation temperature and the amount of catalyst. Since the isomer distribution is not changed by the second-stage phosgenation reaction and the third-stage fractional distillation, the most obtained isomer of MDI is
4,4'-MDI, which is a commercially available MDI,
In many cases, the 4,4'-MDI content was 98% or more.

The MDI composition (a) used in the present invention is
The total of 2,2'-MDI and 2,4'-MDI is 10-5
0% by weight, 4,4'-MDI is 90 to 50% by weight. More preferably, 2,2'-MDI and 2,4'-M
Total DI is 15-40% by weight, 4,4'-MDI is 8
It is 5 to 60% by weight. 2,2'-MDI and 2,4'-
When the total amount of MDI is less than 10% by weight, it is not possible to find a difference in low temperature storage stability of the obtained liquid MDI from the conventional product. Also, 2,2'-MDI and 2,4 '
When the total of -MDI exceeds 50% by weight, there is a problem that the coloring during the carbodiimidization reaction becomes large and the use as a raw material for urethane products is limited.

The MDI composition (b) used in the present invention is
The total of 2,2'-MDI and 2,4'-MDI is 0.1
10% by weight, 4,4'-MDI 99.9 to 90% by weight
Is. More preferably, 2,2'-MDI and 2,4 '
-MDI total 0.5-8 wt%, 4,4'-MDI
Is 99.5 to 92% by weight. Such an MDI is
Since it is the most general-purpose MDI, it has the advantage of low cost.

The MDI composition (c) used in the present invention is
The total of 2,2'-MDI and 2,4'-MDI is 15-6
0% by weight and 4,4'-MDI are 85 to 40% by weight. More preferably, 2,2'-MDI and 2,4'-M
20-50% by weight of total DI, 8 for 4,4'-MDI
It is 0 to 50% by weight. 2,2'-MDI and 2,4'-
When the total amount of MDI is less than 15% by weight, it is not possible to find a difference in low temperature storage stability of the obtained liquid MDI from the conventional product. Also, 2,2'-MDI and 2,4 '
-If the total MDI exceeds 60% by weight, it is not industrially produced and the cost becomes high.

Generally, MDI is used for stabilizing quality.
An antioxidant such as a hindered phenol-based or phosphorus-based antioxidant and a hindered amine-based light stabilizer are added.
These additives may be added to the DI compositions (a) to (c) depending on the application.

As the carbodiimidization catalyst used in the present invention, known catalysts can be used. Examples of the carbodiimidization catalyst include phosphorene-based catalysts and alkylphosphate-based catalysts.

As the phospholene-based carbodiimidization catalyst, 1-phenyl-3-methyl-3-phosphorene-1-
Oxide, 1-methyl-3-methyl-3-phospholen-1-oxide, 1-ethyl-3-methyl-3-phospholen-1-oxide, 1-butyl-3-methyl-3
-Phosphorene-1-oxide, 1- (N-piperidinyl) -3-methyl-3-phospholen-1-oxide,
1-morpholino-3-methyl-3-phosphorene-1-
Oxide, 1-phenyl-3-methyl-2-phospholen-1-oxide, 1-methyl-3-methyl-2-phospholen-1-oxide, 1-ethyl-3-methyl-
2-phospholen-1-oxide, 1-butyl-3-methyl-2-phospholen-1-oxide, 1-phenoxy-3-methyl-2-phospholen-1-oxide, 1
-Phenyl-3-phospholen-1-oxide, 1-methyl-3-phospholen-1-oxide, 1-ethyl-
3-phosphorene-1-oxide, 1-phenyl-2-
Phosphorene-1-oxide, 1-methyl-2-phosphorene-1-oxide, 1-ethyl-2-phosphorene-
1-Oxide, 1-phenyl-3-methyl-3-phosphorene-1-sulfide, a mixture thereof and the like can be mentioned. Among them, 1-phenyl-3-methyl-3-phosphorene-1-oxide, 1 and 1 from the viewpoint of high catalytic activity and the like.
-Phenyl-3-methyl-2-phospholen-1-oxide, 1-phenyl-3-phospholen-1-oxide, 1-phenyl-2-phospholen-1-oxide and the like are preferable.

Examples of the alkyl phosphate-based carbodiimidization catalyst include trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, tris (2-ethylhexyl) phosphate, trioctyl phosphate, triphenyl phosphate, tris (β-chloroethyl) phosphate, tris. (Β-chloropropyl) phosphate, phosphoric acid dimethyl ester, phosphoric acid diethyl ester, phosphoric acid dipropyl ester, phosphoric acid butyl ester, phosphoric acid di (2-
Ethylhexyl) ester, phosphoric acid dioctyl ester, phosphoric acid monomethyl ester, phosphoric acid monoethyl ester, phosphoric acid monopropyl ester, phosphoric acid monobutyl ester, phosphoric acid mono (2-ethylhexyl) ester, phosphoric acid monooctyl ester, and these And the like. Among them, trimethyl phosphate, triethyl phosphate, tributyl phosphate, tris (2-ethylhexyl) phosphate, phosphoric acid dimethyl ester, from the viewpoints of easy availability, cost, catalytic activity and the like.
Phosphoric acid diethyl ester, phosphoric acid dibutyl ester, phosphoric acid di (2-ethylhexyl) ester and the like are preferable.

The conditions for the carbodiimidated uretonimine reaction in the present invention are not affected by the difference between the MDI compositions (a) and (b), but are greatly different between the phospholene type catalyst and the alkyl phosphate type catalyst.

When using a phosphorene-based catalyst, MDI
0.1 to 50 ppm relative to the composition, preferably 0.5
The catalyst is added in an amount of ˜30 ppm and heated to 70 to 150 ° C., preferably 80 to 120 ° C. to allow the reaction to proceed.
The progress of the reaction is confirmed at any time by measuring the content of the residual isocyanate group (hereinafter, abbreviated as NCO group) in the reaction system.
When the CO group reaches 4.76 to 7.62 mmol / g, preferably 5.48 to 7.38 mmol / g, the reaction is stopped by cooling and / or addition of an acid-based reaction terminator.

As the above-mentioned acid-based reaction terminator, hydrogen chloride, nitric acid, sulfuric acid, phosphoric acid, acetic acid, benzoic acid, phthalic acid,
Benzenesulfonic acid, toluenesulfonic acid, naphthalenesulfonic acid, aluminum trichloride, boron trifluoride, boron trichloride, iron trifluoride, iron trichloride, trichlorosilane, diphenyltrichlorosilane, diphenyldichlorosilane, and mixtures thereof. More preferably, phosphoric acid, benzenesulfonic acid, toluenesulfonic acid, naphthalenesulfonic acid, boron trifluoride, boron trichloride, iron trifluoride, iron trichloride, diphenyldichlorosilane, and mixtures thereof. Is.

When an alkyl phosphate-based catalyst is used, 0.05 to 5.00% by weight based on the MDI composition,
The catalyst is preferably added in an amount of 0.1 to 2% by weight,
The reaction is advanced by heating to 0 to 250 ° C, preferably 180 to 230 ° C. The progress of the reaction depends on the remaining N in the reaction system.
Confirm from time to time by measuring the CO group content, and confirm that the NCO group is 4.7
6 to 7.62 mmol / g, preferably 5.48 to
When it reaches 7.38 mmol / g, the reaction is stopped by cooling.

When the residual NCO group content after the carbodiimidization reaction is less than 4.76 mmol / g, the viscosity of the polymer increases remarkably and the workability is not practical. When the NCO group exceeds 7.62 mmol / g, the polyisocyanate composition becomes poor in low-temperature storage stability, and a coating film, elastomer, or
Expected physical properties do not appear in foams.

Both liquid MDI using a phosphorene-based catalyst and liquid MDI using an alkylphosphate-based catalyst can be used as they are after the carbodiimidization reaction has been stopped. However, after the reaction is stopped, aging is performed to obtain carbodiimide. A uretonimine group can also be used. The aging condition is 15 to 70 ° C,
Aging is preferably carried out at 40 to 60 ° C. By uretonimine conversion, a polyisocyanate composition having a stable NCO group content over time can be obtained. The NCO content of the polyisocyanate composition after aging (uretonimine conversion) is 4.52 to 7.38 mmol / g,
It is preferably 5.24 to 7.14 mmol / g.

The liquid MDI that has been manufactured and prepared generally contains 0.1 to 3% by weight of a dimer of MDI (hereinafter abbreviated as MDI dimer) as a by-product. The liquid MDI of the present invention contains the same amount of MDI dimer. Depending on the reaction conditions, the MDI dimer may generate an amount more than the solubility in the liquid MDI and cause turbidity, but in this case, it can be made into a transparent liquid MDI by filtration.

When the MDI composition (c) is added, liquid M
Since it is easy to control the composition of DI, it is preferable to add it after the completion of the uretonimine reaction.
There is no problem even immediately after the completion of the carbodiimidization reaction.

[0027]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In addition,
In the examples, "part" means "part by weight" and "%" means "% by weight".

[Preparation of MDI with Various Mixing Ratios of Isomers] Preparation Example 1 A reactor equipped with a stirrer, a thermometer, a cooling pipe, and a nitrogen gas introduction pipe was equipped with 2,2-MDI and 2,4′-MDI. 5 in total
0% by weight, 140 parts of MDI with 4,4'-MDI of 50% by weight (hereinafter abbreviated as MDI-50), 2,2-MDI
And 2,4'-MDI total 1% by weight, 4,4'-MD
350 parts of MDI (hereinafter, abbreviated as MDI-1) having 99% by weight of I was mixed and stirred at 50 ° C. for 30 minutes to prepare 2,2-M
15% by weight of DI and 2,4'-MDI, 4,4 '
-MDI with 85 wt% MDI was prepared. This MDI
Is MDI-15.

Preparation Example 2 A reactor similar to Preparation Example 1 was charged with 190 MDI-50.
Parts and 300 parts of MDI-1 were mixed and stirred at 50 ° C. for 30 minutes, and the total of 2,2-MDI and 2,4′-MDI was 20.
An MDI having a weight% of 4,4'-MDI of 80% by weight was prepared. This MDI is referred to as MDI-20.

Preparation Example 3 A reactor similar to Preparation Example 1 was charged with 340 MDI-50.
And 150 parts of MDI-1 were mixed and stirred at 50 ° C. for 30 minutes, and the total of 2,2-MDI and 2,4′-MDI was 35.
An MDI having a weight% of 4,4'-MDI of 65% by weight was prepared. This MDI is referred to as MDI-35.

Preparation Example 4 A reactor similar to Preparation Example 1 was charged with 440 MDI-50.
And 50 parts of MDI-1 were mixed and stirred at 50 ° C. for 30 minutes, and the total of 2,2-MDI and 2,4′-MDI was 45% by weight and 4,4′-MDI was 55% by weight. MDI was prepared. This MDI is referred to as MDI-45.

Preparation Example 5 In a reactor similar to Preparation Example 1, 60 parts of MDI-50,
430 parts of MDI-1 were mixed and stirred at 50 ° C. for 30 minutes to obtain MDI having a total of 2,2-MDI and 2,4′-MDI of 7% by weight and 4,4′-MDI of 93% by weight. Prepared. This MDI is referred to as MDI-7. The preparation examples 1 to 5 are shown in Table 1.

[0033]

[Table 1]

In Table 1, the isomer ratio of MDI is JIS
It was measured according to K-0114-1982-8.2. * The gas chromatograph is Shimadzu's GC-9AM (T
CD) Internal standard substance is diphenylmethane

[Example of Liquid MDI] Example 2 A stirrer, a thermometer, an arene cooling pipe, and a nitrogen gas introduction pipe were assembled.
In the reactor, MDI-1 as MDI composition (a)
3000 parts of 5 and trimethyl phosphate (hereinafter, TM
7.5 parts of PAT) was charged and the temperature was raised to 220 ° C. with stirring to carry out a carbodiimidization reaction. N
When the CO content reached 7.05 mmol / g, the reaction vessel was quenched with ice water to 45 ° C. to stop the carbodiimidization reaction. After that, incubate at 45 ℃ for 48 hours,
After converting all of the carbodiimide groups to uretonimine groups,
After cooling to 25 ° C., liquid MDI (2) was obtained. Liquid MD
The MDI content of I (2) was 6.48 mmol / g, and the appearance was a light brown transparent liquid.

Example 3 MDI-as MDI composition (a) in Example 2
Liquid MDI (3) was obtained by reacting in the same manner as in Example 2 except that 15 was changed to MDI-20. Liquid MDI
The MDI content of (3) is 6.48 mmol / g,
The appearance was a light brown transparent liquid.

Example 4 MDI-as MDI composition (a) in Example 2
Liquid MDI (4) was obtained by the same reaction as in Example 2 except that 15 was changed to MDI-35. Liquid MDI
The MDI content of (4) is 6.48 mmol / g,
The appearance was a light brown transparent liquid.

Example 5 The same reactor as in Example 2 was charged with 3000 parts of MDI-45 and 2.4 parts of TMPT as the MDI composition (a), and the temperature was raised to 200 ° C. with stirring. Carbodiimidization reaction was performed. NCO content is 7.05mmo
When it became 1 / g, the carbodiimidization reaction was stopped by quenching the whole reactor with ice water to 45 ° C. Then 4
After keeping the temperature at 5 ° C for 48 hours to convert all of the carbodiimide groups to uretonimine groups, cool to 25 ° C to obtain liquid MD
I (5) was obtained. The MDI content of liquid MDI (5) was 6.48 mmol / g, and the appearance was a light brown transparent liquid.

Example 6 In a reactor similar to that of Example 2 , 3000 parts of MDI-20 as the MDI composition (a), 1-phenyl-3-methyl-3-phospholen-1-oxide (hereinafter PMPO) was used.
Abbreviated as 0.01), and the temperature is set to 9 while stirring.
The temperature was raised to 0 ° C. to carry out a carbodiimidization reaction. NCO
When the content reached 7.05 mmol / g, 0.36 part of β-naphthalenesulfonic acid was added, and the whole reactor was quenched with ice water to 45 ° C. to stop the carbodiimidization reaction. Then, the temperature was kept at 45 ° C. for 48 hours to convert all of the carbodiimide groups to uretonimine groups, and then the mixture was cooled to 25 ° C. to obtain liquid MDI (6). The MDI content of liquid MDI (6) was 6.48 mmol / g, and the appearance was a light brown transparent liquid.

Example 7 MDI-as MDI composition (a) in Example 6
Liquid MDI (7) was obtained by the same reaction as in Example 6 except that 20 was changed to MDI-45. Liquid MDI
The MDI content of (7) is 6.48 mmol / g,
The appearance was a light brown transparent liquid.

Example 8 The same reactor as in Example 2 was charged with 3000 parts of MDI-20 and 9 parts of triethyl phosphate as the MDI composition (a), the temperature was raised to 200 ° C. with stirring, and carbodiimide was added. Was reacted. NCO content is 7.
When it becomes 05 mmol / g, the whole reactor is cooled to 45 ° C with ice water.
To quench the carbodiimidization reaction.
Then, the temperature was kept at 45 ° C. for 48 hours to convert all of the carbodiimide groups to uretonimine groups, and then cooled to 25 ° C. to obtain liquid MDI (8). MD of liquid MDI (8)
The I content was 6.48 mmol / g, and the appearance was a light brown transparent liquid.

Example 9 A reactor similar to that used in Example 2 was charged with 3000 parts of MDI-20 and 12 parts of tributyl phosphate as the MDI composition (a), and the temperature was raised to 200 ° C. with stirring to give a carbodiimide. Was reacted. NCO content is 7.
When it becomes 05 mmol / g, the whole reactor is cooled to 45 ° C with ice water.
To quench the carbodiimidization reaction.
Then, the temperature was kept at 45 ° C. for 48 hours to convert all of the carbodiimide groups to uretonimine groups, and then cooled to 25 ° C. to obtain liquid MDI (9). MD of liquid MDI (9)
The I content was 6.48 mmol / g, and the appearance was a light brown transparent liquid.

Example 10 The same reactor as in Example 2 was charged with 3000 parts of MDI-1 and 7.5 parts of TMPT as the MDI composition (b), and the temperature was raised to 220 ° C. with stirring. Carbodiimidization reaction was performed. NCO content is 6.14 mmol
When it became / g, the reaction vessel was quenched with ice water to 25 ° C to stop the carbodiimidization reaction. Then MD
3620 parts of MDI-35 was charged as the I composition (c) and stirred to obtain a liquid MDI (10) as a uniform liquid. Liquid MDI (10) has an MDI content of 7.18 m.
mol / g, appearance is light brown transparent liquid, composition ratio is 2,2-
20% by weight of MDI and 2,4'-MDI, 4,
The amount of 4'-MDI was 80% by weight (calculated value including those involved in the reaction).

Example 11 A reactor similar to that of Example 2 was charged with 3000 parts of MDI-1 and 7.5 parts of TMpat as the MDI composition (b) and the temperature was raised to 220 ° C. with stirring. Carbodiimidization reaction was performed. NCO content is 6.14 mmol
When it became / g, the carbodiimidization reaction was stopped by quenching the whole reactor with ice water to 45 ° C. Then 45
After keeping the temperature at 48 ° C. for 48 hours to convert all of the carbodiimide groups to uretonimine groups, the mixture was cooled to 25 ° C. Then M
Liquid MDI (11) was obtained as a uniform liquid by charging 3620 parts of MDI-35 as the DI composition (c). Liquid MDI (11) has an MDI content of 6.68 m
mol / g, appearance is light brown transparent liquid, composition ratio is 2,2-
20% by weight of MDI and 2,4'-MDI, 4,
The amount of 4'-MDI was 80% by weight (calculated value including those involved in the reaction).

Example 12 The same reactor as in Example 2 was charged with 3000 parts of MDI-15 as an MDI composition (a) and 3.8 parts of TMPT.
4.9 parts of phosphoric acid dibutyl ester was charged and the temperature was raised to 200 ° C. with stirring to carry out a carbodiimidization reaction. When the NCO content reaches 5.71 mmol / g,
The carbodiimidization reaction was stopped by quenching the whole reactor with ice water to 45 ° C. Then, the temperature was kept at 45 ° C. for 48 hours, all of the carbodiimide groups were converted to uretone imine groups, and then cooled to 25 ° C. to obtain liquid MDI (12).
The MDI content of liquid MDI (12) is 4.32 mmol
/ G, and the appearance was a light brown transparent liquid.

Example 13 The same reactor as in Example 2 was charged with 3000 parts of MDI-15 and 7.5 parts of TMpat as the MDI composition (a) and the temperature was raised to 220 ° C. with stirring. Carbodiimidization reaction was performed. NCO content is 7.05mmo
When it became 1 / g, the carbodiimidization reaction was stopped by quenching the whole reactor with ice water to 45 ° C. Then 4
After incubating at 5 ° C for 15 hours, a part of carbodiimide group was converted to uretonimine group, and then cooled to 25 ° C to obtain liquid MD
I (13) was obtained. The NCO content of the liquid MDI (13) was 6.75 mmol / g, and the appearance was a light brown transparent liquid.

Example 14 A reactor similar to that of Example 2 was charged with 3000 parts of MDI-1 and 7.5 parts of TMpat as the MDI composition (b), and the temperature was raised to 220 ° C. with stirring. Carbodiimidization reaction was performed. NCO content is 6.14 mmol
When it became / g, the carbodiimidization reaction was stopped by quenching the whole reactor with ice water to 45 ° C. Then 45
The temperature was kept at 15 ° C. for 15 hours to convert a part of the carbodiimide group to a uretone imine group, and then cooled to 25 ° C. Then M
Liquid MDI (14) was obtained as a uniform liquid by charging 3620 parts of MDI-35 as DI composition (c). Liquid MDI (14) has an MDI content of 6.94 m.
mol / g, appearance is light brown transparent liquid, composition ratio is 2,2-
20% by weight of MDI and 2,4'-MDI, 4,
The amount of 4'-MDI was 80% by weight (calculated value including those involved in the reaction).

Comparative Example 1 Liquid MDI was reacted in the same manner as in Example 2 except that MDI-15 in Example 2 was changed to MDI-1.
(Ratio 1) was obtained. The MDI content of liquid MDI (ratio 1) was 6.48 mmol / g, and the appearance was a light brown transparent liquid.

Comparative Example 2 Liquid MDI was reacted in the same manner as in Example 6 except that MDI-20 in Example 6 was changed to MDI-1.
(Ratio 2) was obtained. The MDI content of liquid MDI (ratio 2) was 6.48 mmol / g, and the appearance was a light brown transparent liquid.

Comparative Example 3 Liquid MDI was reacted in the same manner as in Example 8 except that MDI-20 in Example 8 was changed to MDI-7.
(Ratio 3) was obtained. The MDI content of liquid MDI (ratio 3) was 6.48 mmol / g, and the appearance was a light brown transparent liquid. Examples 2 to 14 are shown in Tables 2 to 4, and Comparative Examples 1 to 3 are shown in Table 5.

[0051]

[Table 2]

[0052]

[Table 3]

[0053]

[Table 4]

[0054]

[Table 5]

In Tables 2 to 5, TMCAT: trimethyl phosphate TEPAT: triethyl phosphate PMPO: 1-phenyl-3-methyl-3-phospholen-1-oxide TBPAT: tributyl phosphate DBPAT: dibutyl phosphate * NCO group content: JIS K-1603-1985
According to -5.3

[Storage Stability Test] Liquid MDIs obtained in Examples 2 to 14 and Comparative Examples 1 to 3.
Put in a 200 ml sample bottle, -5 ℃, 0 ℃, 10
A storage stability test was conducted at 25 ° C and 25 ° C. The change with time was visually observed for the presence or absence of crystal precipitation on a half-day basis. The measurement results are shown in Tables 6 and 7. MDIs obtained in Comparative Examples 1 to 3
In (Ratio 1) to (Ratio 3), precipitation of crystals is confirmed within 1 day at -5 ° C, whereas in the MDIs (2) to (14) obtained in Examples 2 to 14, No precipitation of crystals was confirmed at -5 ° C for at least 15 days, which proved to be advantageous for storage and use in winter and cold regions.

[0057]

[Table 6]

[0058]

[Table 7]

[0059]

INDUSTRIAL APPLICABILITY The liquid MDI of the present invention is excellent in storage at a low temperature for a long time, which cannot be obtained by the conventional liquid MDI, without considering the preservation method particularly for preservation in winter or cold regions. It showed stability.

Claims (4)

(57) [Claims] 1. An isocyanate group is carbodiimidized.
Components of polyisocyanate composition including those
With 2,2'-diphenylmethane diisocyanate
The total of 2,4'-diphenylmethane diisocyanate is
10 to 50% by weight, and 4,4'-diphenylmethanedi
Diphenyl with 90-50% by weight of isocyanate
Carbodiimidating part of methane diisocyanate
In the resulting polyisocyanate composition, 2,2'-diphenylmethane diisocyanate and 2,
The total of 4'-diphenylmethane diisocyanate is 0.
1-10% by weight, and 4,4'-diphenylmethanediii
Dipheni containing 99.9-90% by weight of cyanate
In the methane diisocyanate composition (b), carbodiimi
Addition catalyst and heated to diphenylmethane diisocyanate
A part of the nate composition (b) is carbodiimidized,
2,2'-diphenylmethane diisocyanate and 2,
The total amount of 4'-diphenylmethane diisocyanate is 15
~ 60% by weight, and 4,4'-diphenylmethanediiso
Cyanate is 85 to 40% by weight of diphenyl meta
And a diisocyanate composition (c) are mixed.
A polyisocyanate group with excellent low temperature storage stability
Method for producing a product. 2. A polyisocyanate composition obtained by carbodiimidating a part of diphenylmethane diisocyanate and uretoniminating the generated carbodiimide group, including those in which the isocyanate group is carbodiimidated and uretoniminated or uretoniminated. The components of the polyisocyanate composition are 2,2'-diphenylmethane diisocyanate and 2,2'-diphenylmethane diisocyanate.
The total amount of 4'-diphenylmethane diisocyanate is 10
A polyisocyanate composition having excellent low-temperature storage stability, characterized in that the polyisocyanate content is from 50 to 50% by weight, and the content of 4,4'-diphenylmethane diisocyanate is from 90 to 50% by weight. 3. A diphenylmethane diisocyanate composition comprising 10 to 50% by weight of 2,2'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate in total and 90 to 50% by weight of 4,4'-diphenylmethane diisocyanate ( added carbodiimidization catalyst in a), heated to carbodiimidization part of diphenylmethane diisocyanate composition (a), the then resulting carbodiimide group cold storage stability according to claim 2, characterized in that the uretonimine of A method for producing an excellent polyisocyanate composition. 4. Diphenylmethane in which the total of 2,2'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate is 0.1 to 10% by weight, and 4,4'-diphenylmethane diisocyanate is 99.9 to 90% by weight. A carbodiimidization catalyst was added to the diisocyanate composition (b) and heated to carbodiimidate a part of the diphenylmethane diisocyanate composition (b), and then the carbodiimide group formed was uretoniminated, and further, 2,2'-diphenylmethane diisocyanate was added thereto. A diphenylmethane diisocyanate composition (c) comprising 15 to 60% by weight of a total of 2,4'-diphenylmethane diisocyanate and 85 to 40% by weight of 4,4'-diphenylmethane diisocyanate is mixed. The method for producing a polyisocyanate composition having excellent low-temperature storage stability according to claim 2 .